How to compress a PDF for email

Step by step

1. Open Compress PDF. Go to the Compress PDF page on PlumPDF. No sign-up and nothing to install.
2. Add your PDF. Drop the file on the box, or click to browse. Files up to 100 MB are accepted.
3. Pick a level. Start with Recommended. If the file is still too big, run it again on Strong.
4. Compress and compare. Press Compress PDF. You see the old and the new size before you save the file, so you know whether it will fit.

Why do PDFs get too big to email?

Many email services limit attachments to roughly 20 to 25 MB, and some recipients' mailboxes are stricter. A PDF that is mostly text is small. The trouble starts with pictures: scanned pages, photos from a phone and screenshots. A photo printed 10 cm wide does not need 4000 pixels across, yet that is often what is stored inside the file.

What do the three compression levels do?

PlumPDF changes only the images, and the level sets how far they are reduced:

• Light keeps images up to 200 DPI at JPEG quality 85.
• Recommended keeps images up to 150 DPI at quality 72, which suits most documents.
• Strong keeps images up to 110 DPI at quality 60, for the smallest file.

Honest limits

How much smaller the file gets depends on what is inside it. Scans and PDFs full of phone photos often shrink by half or more. A PDF that is mostly text has little to remove. If the result is not smaller, PlumPDF tells you and you keep the original.

Some images are always left alone, such as ones with transparent parts, print-colour images and black-and-white fax-style scans. In a scanned document the whole page is a picture, so at the Strong level the text can look a little softer.

What if the PDF is still too large?

Split the PDF into two parts with Split PDF and send them in separate emails. For a scan that does not need colour, Greyscale PDF can help too. Check the result on screen before you send it, and keep the original.

Questions